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I didn’t catch it either at first! We’re so used nowadays to have everything go through the processor. But early consumer grade PowerPCs weren’t that powerful and surely couldn’t do realtime video, especially with the limitations of Mac OS 9 multitasking. So to be able to use your computer while...

Output of the TV tuner goes through the AV card and the output of the AV card is then layered on top of the video from the internal graphics chip, in the analog space. It’s a trickery to not use any computational resources! That’s why it doesn’t work on a monitor plugged into an additional PCI...

It’s Picture In Picture, in the analog space, just like a fancy CRT TV from the same era.

Providing someone can identify the chips: The small one is a quad video amp, but I was unable to find the big one (I only did a quick search, I’m not a specialist in chip identification)

It may well completely bypass the VRAM, and directly output the upscaled signal in the analog space… (no insight, just speculating)

I’ve done it a few times, with aluminum brackets and double sided foam tape: Used the original drive as a template to properly align everything: Nuts are stuck to the aluminum with superglue!

And the AGP bus is non standard on Macs with an ADC port for video: it carries USB data lines. (That’s why you have to tape or cut two pins on a PC card flashed for Mac)

Did you try to run it naked, outside of the acrylic shell? IIRC there’s a gasket inside the acrylic shell, around the place for the power button, that could cause erratic behavior. It’s safe to remove it, it was even documented by Apple.

Those holes aren’t for lubrication, what you see at the back of the sticker are the remnants of a decayed soft foam whose purpose was to clean the rollers.

Made some tests recently with L2 caches and 6400/6500 motherboards : The IDT7MPV6284 - 512KB L2 cache doesn’t seem to work with a 6400 (200MHz) motherboard : the Mac chimes but does not boot, no video, and the power led doesn’t even light up! With a 6500 (225MHz) motherboard, the 512KB L2...

Is there a way to dump the ROM of these machines? Maybe their ROMs are different?

I did that when I owned a MessagePad and my original power supply wasn’t working properly: the modern replacement PSU didn’t work! The MessagePad seems to be very picky about the exact input voltage: it gave me an error message (don’t remember exactly what it was) and straight up refuse to...

The soft plastic coating can break down with age and become sticky and unpleasant to the touch. I don’t know if it’s fixable, especially long term. (It happened with my MessagePad 2000, ended up selling it because of that)

Good to know that the differences are minimal. One day I’ll tear down my TAM just to see by myself how they Frankensteined the whole thing!

Ooh, that’s interesting! It’s even interesting the other way around: if we could document the differences between a 5500/6500 logic board and a TAM one, it would allow to replace it more easily in case of failure or even make a 300MHz TAM! I will have a 5500 LB in a few days, found one cheap. I...

Im curious, why are you interested in those particular resistors?

Should I get my TAM out of his box? I won’t tear it down! ;)

They’re on the underside!? Here’s a picture of the underside of a 6500: it seems to me that R273 is near the bottom right corner of the square TI chip. (couldn’t find the other ones)

FWIW, there’s a picture of a (dusty) TAM motherboard on iFixit. Where are those resistors located? I couldn’t find them!

I’m sure many of you know this, but blue LEDs aren’t accurate for 80s and early 90s computers. They didn’t exists back in the day. There even was an issue of the electronics magazine Elektor in the late eighties (IIRC) that was asking on the front page wether we would see blue LEDs in the...